Angular - Version upgrade to v21

[erdemcaygor]

Upgrade Angular framework to version 21 to align with the latest stable release

Angular packages

• [ ] migrate ng-schematics

Update 3rd party packages

• [ ] angular-oauth2-oidc
• [ ] ng-bootstrap
• [ ] ng-zorro-antd

Other updates

• [ ] commerical demo will be updated here https://github.com/volosoft/vs-internal/issues/7829
• [ ] studio templates will be updated here https://github.com/volosoft/abp-studio/issues/4089
• [ ] doc updates will be done here https://github.com/abpframework/abp/issues/24385